1. Field of the Invention
The invention relates to the field of LED packaging and LED arrays comprised of a plurality of LED packages using color controlled LED's.
2. Description of the Prior Art
The typical LED package consists of an LED emitter, a lead frame to transfer electric current to the LED emitter, a thermal transfer means, which may also be the lead frame, possibly an encapsulant and a lens or protective dome, which may also be the encapsulant. A typical white LED is comprised additionally of a phosphor coating over a “blue” LED emitter. Much instruction in the prior art is dedicated to describing the processes for applying this phosphor to the blue LED.
Some LED packages are manufactured with three different colored LED emitters, most often red, green and blue, and provide a wide range of color, including white, when the emitters are controlled individually. The LED emitters are closely spaced and when seen from a distance appears to be one color. The problem with these devices, however, is when an optic is required on the device to narrow the beam, the rays of the resultant beam are split into separate beams which do not share the same angle space, because the sources are in different locations within the focus of the optic required to narrow the beam.
When applied to products, such as flood lights or backlight illumination, the resultant separation of color is at least annoying if not unacceptable. In a typical flood light, the perimeter of a spot projected on the wall will have a fringe of varying colors.
The typical solution to this color variance is to apply at least one layer of diffusing material in the beam to “homogenize” the light output. This usually results in a sever loss of light level and unwanted spreading and bleeding of light from the system.
What is needed is a controllable, combined light source which is not subject to the inherent disadvantages of such prior art.